Water

Question 1

Hypotonic

Answer 1

There is a higher water potential outside the cell than in the solution so water diffuses out of the cell and into the solution to balance the water ratio, this causes crenation

Question 2

Hypertonic

Answer 2

There is a higher water potential outside of the cell than inside so the water from the solution diffuses into the cell to balance the water, this causes lysis

Question 3

Isotonic

Answer 3

There is a balanced water potential between cell and solution so there is no change in animal cell

Question 4

Osmosis

Answer 4

Osmosis is the net movement of water from a high water potential to a low water potential through a semi-permeable membrane

Question 5

Urine

Answer 5

A solution containing water,urea and other waste products (e.g salts)

Question 6

Urea

Answer 6

Produced by the liver when excess amino acids are broken down.
-toxic- must be removed from the body via urinary system via excretion

Question 7

Ultrafiltration

Answer 7

-blood enters kidney through renal artery into the glomerulus
-increase in blood pressure as blood vessel narrows
-small molecules(e.g. glucose, salt, water,urea) forced out from the glomerulus into the bowman’s capsule
-only protein and blood cells remain in body——> can’t pass across semi-permeable membrane

Question 8

Selective reabsorption

Answer 8

-As the filtrate moves through the nephron, useful substances are reabsorbed in the: proximal convoluted tubule: all glucose (respiration) = active transport
-loop of henle: some water and salt-diffusion
-other substances (all urea,some water , some salts) are not

Question 9

Osmoregulation

Answer 9

-the urine collects in the collecting duct- a place for selective reabsorption of water into the bloodstream

More water reabsorption = more urine

Less water reabsorbed = dilute urine

Urine sent to the bladder for excretion

Question 10

ADH(Anti diuretic hormone)

Answer 10

-controls the water volume in the blood via negative feedback
-changes the permeability of the collection duct
-produced by the pituitary gland
-can be produced due to low blood water concentration
(e.g sweating, dehydration, consumption of salty/ sugary food)

Question 11

ADH (Anti diuretic hormone) example

Answer 11

-osmoreceptors- in the hypothalamus detects low water potential
-stimulates pituitary gland to produce lots of ADH
-ADH travels in the bloodstream to the collecting duct = makes it more permeable
-more water from the urine to the bloodstream(more being reabsorbed from collecting duct)
-small volume of concentrated urine (dark colour)

Question 12

High blood water concentration (e.g excessive drinking of water)

Answer 12

-osmoreceptors in the hypothalamus detects high water potential
-stimulates pituitary gland less to produce less ADH
-the collecting duct is less less permeable
-Less water is reabsorbed from the urine to the blood stream (more remains)
=large volume of dilute,clear urine